<?php

/**
 * @package dompdf
 * @link    http://www.dompdf.com/
 * @author  Benj Carson <benjcarson@digitaljunkies.ca>
 * @author  Fabien M�nager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: page_frame_reflower.cls.php 448 2011-11-13 13:00:03Z fabien.menager $
 */

/**
 * Reflows pages
 *
 * @access private
 * @package dompdf
 */
class Page_Frame_Reflower extends Frame_Reflower {

    /**
     * Cache of the callbacks array
     * 
     * @var array
     */
    private $_callbacks;

    /**
     * Cache of the canvas
     *
     * @var Canvas
     */
    private $_canvas;

    /**
     * The stacking context, containing all z-indexed frames
     * @var array
     */
    private $_stacking_context = array();

    function __construct(Page_Frame_Decorator $frame) {
        parent::__construct($frame);
    }

    /**
     * @param $frame Frame
     * @return void
     */
    function add_frame_to_stacking_context(Frame $frame, $z_index) {
        $this->_stacking_context[$z_index][] = $frame;
    }

    function apply_page_style(Frame $frame, $page_number) {
        $style = $frame->get_style();
        $page_styles = $style->get_stylesheet()->get_page_styles();

        // http://www.w3.org/TR/CSS21/page.html#page-selectors
        if (count($page_styles) > 1) {
            $odd = $page_number % 2 == 1;
            $first = $page_number == 1;

            $style = clone $page_styles["base"];

            // FIXME RTL
            if ($odd && isset($page_styles[":right"])) {
                $style->merge($page_styles[":right"]);
            }

            if ($odd && isset($page_styles[":odd"])) {
                $style->merge($page_styles[":odd"]);
            }

            // FIXME RTL
            if (!$odd && isset($page_styles[":left"])) {
                $style->merge($page_styles[":left"]);
            }

            if (!$odd && isset($page_styles[":even"])) {
                $style->merge($page_styles[":even"]);
            }

            if ($first && isset($page_styles[":first"])) {
                $style->merge($page_styles[":first"]);
            }

            $frame->set_style($style);
        }
    }

    //........................................................................

    /**
     * Paged layout:
     * http://www.w3.org/TR/CSS21/page.html
     */
    function reflow(Frame_Decorator $block = null) {
        $fixed_children = array();
        $prev_child = null;
        $child = $this->_frame->get_first_child();
        $current_page = 0;

        while ($child) {
            $this->apply_page_style($this->_frame, $current_page + 1);

            $style = $this->_frame->get_style();

            // Pages are only concerned with margins
            $cb = $this->_frame->get_containing_block();
            $left = $style->length_in_pt($style->margin_left, $cb["w"]);
            $right = $style->length_in_pt($style->margin_right, $cb["w"]);
            $top = $style->length_in_pt($style->margin_top, $cb["h"]);
            $bottom = $style->length_in_pt($style->margin_bottom, $cb["h"]);

            $content_x = $cb["x"] + $left;
            $content_y = $cb["y"] + $top;
            $content_width = $cb["w"] - $left - $right;
            $content_height = $cb["h"] - $top - $bottom;

            // Only if it's the first page, we save the nodes with a fixed position
            if ($current_page == 0) {
                $children = $child->get_children();
                foreach ($children as $onechild) {
                    if ($onechild->get_style()->position === "fixed") {
                        $fixed_children[] = $onechild->deep_copy();
                    }
                }
                $fixed_children = array_reverse($fixed_children);
            }

            $child->set_containing_block($content_x, $content_y, $content_width, $content_height);

            // Check for begin reflow callback
            $this->_check_callbacks("begin_page_reflow", $child);

            //Insert a copy of each node which have a fixed position
            if ($current_page >= 1) {
                foreach ($fixed_children as $fixed_child) {
                    $child->insert_child_before($fixed_child->deep_copy(), $child->get_first_child());
                }
            }

            $child->reflow();
            $next_child = $child->get_next_sibling();

            // Check for begin render callback
            $this->_check_callbacks("begin_page_render", $child);

            $renderer = $this->_frame->get_renderer();

            // Render the page
            $renderer->render($child);

            Renderer::$stacking_first_pass = false;

            // http://www.w3.org/TR/CSS21/visuren.html#z-index
            ksort($this->_stacking_context);

            foreach ($this->_stacking_context as $_frames) {
                foreach ($_frames as $_frame) {
                    $renderer->render($_frame);
                }
            }

            Renderer::$stacking_first_pass = true;
            $this->_stacking_context = array();

            // Check for end render callback
            $this->_check_callbacks("end_page_render", $child);

            if ($next_child) {
                $this->_frame->next_page();
            }

            // Wait to dispose of all frames on the previous page
            // so callback will have access to them
            if ($prev_child) {
                $prev_child->dispose(true);
            }
            $prev_child = $child;
            $child = $next_child;
            $current_page++;
        }

        // Dispose of previous page if it still exists
        if ($prev_child) {
            $prev_child->dispose(true);
        }
    }

    //........................................................................

    /**
     * Check for callbacks that need to be performed when a given event
     * gets triggered on a page
     *
     * @param string $event the type of event
     * @param Frame $frame the frame that event is triggered on
     */
    protected function _check_callbacks($event, $frame) {
        if (!isset($this->_callbacks)) {
            $dompdf = $this->_frame->get_dompdf();
            $this->_callbacks = $dompdf->get_callbacks();
            $this->_canvas = $dompdf->get_canvas();
        }

        if (is_array($this->_callbacks) && isset($this->_callbacks[$event])) {
            $info = array(0 => $this->_canvas, "canvas" => $this->_canvas,
                1 => $frame, "frame" => $frame);
            $fs = $this->_callbacks[$event];
            foreach ($fs as $f) {
                if (is_callable($f)) {
                    if (is_array($f)) {
                        $f[0]->$f[1]($info);
                    } else {
                        $f($info);
                    }
                }
            }
        }
    }

}
